There is an ever-increasing demand for electrical motor drive systems which possess the desirable accelerating and driving characteristics of internal combustion engines coupled with automatic transmissions while avoiding the problems of severe pollution and energy consumption. Electrical motor drives which have been devised for use in motor vehicles require a battery system which is excessively large in order to provide the necessary power and motive force. Even with the utilization of large battery systems, however, the range of such vehicles has been limited and the available horsepower is extremely low when compared with the internal combustion engine. Further, highly complex electrical control circuitry has been employed in the past to correlate the characteristics of the electric motor drive with the operating requirements of the vehicle, primarily due to the comparatively low horsepower capacity of electric motors and the extent towhich their operating efficiency is affected by the speed at which they are run. Representative of the approaches heretofore undertaken in the development of electrical motor drives is U.S. Letters Patent to Tabor U.S. Pat. No. 3,858,674 which discloses a flywheel drive for an electric car wherein the flywheel is coupled to a torque converter to vary the speed ratio. U.S. Letters Patent to Locker et al. U.S. Pat. No. 4,065,702 discloses the use of a flywheel to control a variable speed unit for adjustment of the speed of a motor of an electric drive vehicle. Other patents which employ a similar approach are U.S. Pat. No. 3,476,201 to Swaine and U.S. Pat. No. 3,497,026 to Calvert.
It has also been proposed in the past to employ infinitely variable speed drive transmissions in automotive vehicles. For instance, U.S. Pat. No. 3,237,468 to Schottler discloses a ball and race type power transmission which is designed to transmit high torque between a drive and driven shaft through a wide range of speed ratios and employs a speed governor to operate the transmission at the highest possible speed ratio in order to achieve maximum efficiency and performance. Other patents directed to similar types of infinitely variable speed transmissions are U.S. Pat. Nos. 3,071,018 to Floyd; 3,248,960 and 3,745,844 to Schottler; also, 2,727,396 to Haugwitz. These patents however do not address themselves to the problems peculiar to the use of a battery-operated DC motor as a power source for motor vehicles and especially to the problem of avoiding the sophisticated and complex electronic circuitry heretofore required to control a DC motor.